Learn Hardcore Japanese: watasi ha karita nooto wo asita kaesimasu. - I will return the notebook I borrowed tomorrow.

In Japanese, a verb in its plain form (including past tenses) can directly modify a noun, just like a relative clause in English. Here, 借りたノート literally means “the notebook (ノート) that (I) borrowed (借りた).” The past tense 借りた signals that the action of borrowing is already completed.

What does the particle を after ノート do?

The particle を marks ノート as the direct object of the verb 返します. It tells you what is being returned. In English you’d say “return the notebook”; in Japanese it’s “ノートを返します.”

Why is 私 followed by は instead of が?

は is the topic marker: it sets 私 (“I”) as the topic of the sentence (“As for me, …”). が would mark 私 as the grammatical subject with a nuance of new or emphasized information. In a simple statement like “I will return…,” は is the natural choice.

Why is 明日 placed before the verb instead of at the very beginning?

Time expressions like 明日 (“tomorrow”) are flexible in Japanese and typically come before the verb. You could say 明日、私は… or 私は明日…. Placing it right before the verb keeps the core “what I will do” together.

How does 返します express a future action? Isn’t it present tense?

Japanese doesn’t have a separate future tense. The non-past form (sometimes called “present tense”) covers both present and future actions. Context tells you it’s happening tomorrow, so 返します is understood as “will return.”

Could you omit 私 in this sentence?

Yes. Japanese often drops clear subjects. If the context already makes it clear that you’re the one returning the notebook, you can say 借りたノートを明日返します。

What’s the difference between 借りる and 貸す?

借りる means “to borrow/receive something from someone.”
貸す means “to lend/give something to someone.”
Since you received (borrowed) the notebook, you describe it with 借りたノート.

Why is ノート written in katakana?

ノート is a loanword from English “note.” In Japanese, many foreign-origin words are written in katakana to set them apart from native vocabulary.

Why use 返す/返します instead of 戻す?

返す (かえす) means “to give back something to its owner.”
戻す (もどす) means “to put something back to its original place” (not necessarily back to an owner). Since you’re returning a borrowed item to the lender, 返す is the correct verb.